Re-terminating balanced AKG K702's with Hirose HR10A-7P-6P connector for iBasso.
Feb 26, 2011 at 2:08 PM Thread Starter Post #1 of 10

chum_2000_uk

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Hi guys,
 
Just a quick question; I am going to re-terminate my balanced AKG's for a fellow head-fier who is buying them off me. Instead of the 4-Pin XLR that is on there now, he needs a Hirose 6 pin connector on there. On the iBasso website it has a pinout diagram:
 
http://www.ibasso.com/en/products/show.asp?ID=59
 
as you can see the diagram states (for balanced headphones) that pin 1 and 4 are "NC". I assume that basically means "Not Connected" or something to that effect? In this case it's just a case of simply soldering the L&R ch + and - wires the same as when terminating with a 4-pin XLR (but obviously ensuring to solder according to the pinout I have linked to above) correct?
 
I have already re-terminated two of my other headphones with 4-pin XLR connectors, so I am comfortable doing this.
 
Cheers guys!
 
Feb 28, 2011 at 1:57 PM Post #3 of 10
Yes, NC means not connected. You may want to rethink the hirose connector however. You would be terminating the phones in an even more proprietary connector than what you have on there now. How about making an adapter cable instead?
 
Feb 28, 2011 at 2:18 PM Post #4 of 10
Hey Pars, thanks for the reply!
 
It's not really my choice, the Hirose receptacle is what is on the guy's balanced amp, and I'm just doing a quick connector swap for him for basically not much more than the cost of the connector I've ordered on his behalf. If I factor in my time and fuel going to collect the part from the trade counter etc, I'm probably at a loss by doing this for him, but I don't mind to help a fellow member out. Having said that, I don't really fancy messing around trying to make an adapter. I don't really have any nice cable here, or any nylon multifilament to make it look decent etc.
 
Couldn't it be argued that by using an additional adapter you could potentially be losing more quality like that anyway? What you think? I never tend to worry too much about these kind of things, I just try and weigh up cost vs quality (by usually just going for Neutrik connectors) and then do as neat a job as I can soldering the connector using decent quality WBT solder.
 
 
 
 
Mar 3, 2011 at 3:15 PM Post #5 of 10
I don't worry about additional connections, particularly in a situation like this. Of course some people claim they can identify the connector plating by sound... I'm not one of them
rolleyes.gif

 
I wonder if they can tell what kind of wire was used in the device packages in the signal path? And the circuit board plating? :rofl:
 
Mar 3, 2011 at 3:55 PM Post #6 of 10
Yeah I agree tbh Pars. And I have to confirm that the Hirose connector was an absolute POS to work with. Whoever designed that connector was an idiot, particularly the way it assembles and disassembles - basically you have to screw the centre of the connector (the part with the male pin contacts) out from the front by using a small spanner on the end where the cable goes into and somehow trying to hold the inner section still.
 
Once apart, it is a bitch of a job soldering the wires to the tiny and close together contacts. But the worst part is then trying to put it all back together. I think I did a neat job of soldering the wires, but can't be 100% sure that I didn't break any of the solder joints while trying to reassemble the bloody thing. I have no way of testing it either, so I am praying that it is going to work for the fella I have sold them to.
 
So yeah, a warning to try and avoid this connector like the plague if possible, god knows why iBasso decided to use it! 
 
Mar 4, 2011 at 1:09 AM Post #7 of 10
If you have a multimeter (DMM), you could ohm out L+ to L- and R+ to R- to verify that you have connections. I'm not sure what the AKG drivers should ohm out to, but I would guess somewhere in the range of 20 to 100 ohms maybe? Then check all pins to each other to make sure you don't have any shorts. Good luck.
 
Mar 4, 2011 at 5:40 AM Post #8 of 10
I do have a DMM, but in order to check the continuity I would have had to have exposed the wire elsewhere back towards the drivers. Probably the only way of doing that would have been to take the grilles off, which I've heard can be a bit awkward on the K702's, so I didn't want to risk damaging them before sending them off.
 
As for shorts between the contacts, I'm 99% sure there are none, I inspected the soldering really close with my magnifying lamp.
 
The headphones are on their way now, so fingers crossed the connector will work first time.
 
**Edit, sorry I didn't quite read your previous post properly about the checks, I see now what you mean about ohming out L+ to L- etc. Didn't think of that! Good tip for next time - thanks!
 
Mar 5, 2011 at 10:33 PM Post #9 of 10
These really suck to solder.  The way I do it is to cut tiny pieces of teflon tube to cover each of the solder cups except for the one I"m currently soldering, and then slide on a tiny piece of shrink onto the wire before it goes on, and brush liquid flux onto the contacts to help them tin easier.  Still, not fun.  
 

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